I've just been told of a Mk3 Spitfire, OML 845E, which is going under the hammer at the Charterhouse Auction in a couple of weeks time, on Sunday 19th July at the 'Classics at the Castle' show at Sherborne Castle.
The car has a fastback body on it and there seems to be some thought that it was a works prototype, but I'm not sure where that information came from, as that's not made clear on the auction details. I'd be very interested to hear if anyone does know any more about this car and its modifications. It's not a car that I've previously heard of on the Register or otherwise.
More information can be found at the Charterhouse website: http://preview.charterhouse-auction.com/2015/06/1967-Triumph-Spitfire-MkIII-GT.html
Suzie
Early Spitfire Register Secretary